At the turn of the last century, San Francisco could fairly count itself as one of the world's great cities. Formed out of the gold rush of 1849, it transformed from a rough-and-tumble mining town into a cosmopolitan center of 400,000 people. Aspirational locals called it the Paris of the West. There were fashionable department stores, urbane hotels, a new sprawling city hall said to be the biggest in the West, and a Grand Opera House that hosted the greatest tenor of that time, Enrico Caruso. All of that changed on April 18, 1906.

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At 5:12 am, a powerful earthquake centered just off the coast grabbed San Francisco by the throat and nearly shook it to death. The magnitude 7.8 quake arrived in two pulses, the second more powerful than the first. "[It] hurled my bed against an opposite wall," wrote Emma Burke, the wife of a local attorney. "It grew constantly worse, the noise deafening; the crash of dishes, falling pictures, the rattle of the flat tin roof, bookcases being overturned, the piano hurled across the parlor, the groaning and straining of the building itself, broken glass and falling plaster, made such a roar that no one noise could be distinguished."

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Sea captains said it felt as though their boats had run into a sea of rocks. Wooden houses splintered, cracked and collapsed, while poorly reinforced brick buildings tumbled to the ground. Bleary residents scurried into streets that were rippling like waves and firing off cobblestones. Trees whipsawed, telephone poles snapped and streetcar rails buckled. Amidst the noise, all of San Francisco's church-tower bells rang out, sounding an eerie alarm that lasted until the shaking stopped nearly a minute after it had begun.

If the epicenter of the earthquake was 2 miles out in the sea on the San Andreas Fault, the focal point of the quake's damage was in the working-class neighborhood south of Market Street. When the shock waves rippled through this reclaimed swampland, they temporarily liquefied the man-made ground, causing scores of buildings to collapse. Several hotels were destroyed, including the four-story Valencia Street Hotel, which pancaked to street level; top-floor guests simply stepped outside. Chinatown, just north of Market Street, was also particularly hard hit because of the extensive use of unreinforced brick masonry.

Like the second seismic shock wave, the quake sparked dozens of fires to life, causing a second, more powerful pulse of destruction. The tremors had broken the city's fire alarm system, but firefighters could see enough smoke billowing up to know where to go. They hooked fire hoses to hydrants, but when they opened the valves no water gushed forth. Most of the city's water lines had ruptured, too.

The tightly packed wooden-frame construction concentrated south of Market Street made fast fuel for a blaze that jumped from building to building and from block to block. What was later dubbed the "ham and eggs fire" burned down the house of a family cooking breakfast and then swept east until it had completely destroyed a local college, San Francisco's Hall of Records and the massive City Hall. Walls of fire converged from all angles until smoke filled the sky, as if San Francisco itself had erupted.

"Within an hour after the earthquake shock, the smoke of San Francisco's burning was a lurid tower visible a hundred miles away," wrote Jack London, who rode from his ranch in Glen Ellen to San Francisco on the day of the quake. "And for three days and nights this lurid tower swayed in the sky, reddening the sun, darkening the day, and filling the land with smoke."

San Franciscans quickly retreated, hauling in trunks what possessions they could. Navy boats and local firefighters had saved the city's wharf, a feat that allowed tens of thousands to leave the city. Others fled to high ground at Telegraph Hill and at Lafayette Square in the Western Addition. Men in dark ties and bowler hats and women in heavy dresses stared in disbelief as the 2000-degree inferno incinerated their city.

The fate for those still trapped by earthquake rubble was much, much worse. At the collapsed Valencia Street Hotel, rescuers dug feverishly to free survivors, but were forced to retreat as the fire descended. An estimated 100 people didn't make it out of the rubble.

The blaze was so strong it even created its own weather pattern, drawing storm-force winds to feed itself with oxygen. "Near the flames, the wind was often half a gale, so mighty was the suck," wrote London. With the hydrants empty, firefighters tried to pump what little water they could out of the sewer lines beneath the streets — it didn't amount to much.

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The city's fire chief, Dennis Sullivan, appreciated the hazards of a city tightly clustered with wooden buildings, and in the year before the earthquake had spoken of dynamiting buildings to create firebreaks in the event of massive fires. But the chief was mortally injured in the first minutes of the 1906 quake, and with him went any semblance of a plan. His successor, John Dougherty, had no expertise with dynamite. He contacted the Army base at the Presidio and asked for their help. Gen. Frederick Funston, the brigadier general in charge, ordered his troops into the streets to maintain order and to assist with the explosive demolition.

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In a story he wrote in the July 1906 issue of Cosmopolitan magazine, Funston recalled the dynamite experiment. "I doubt if anyone will ever know the amount of dynamite and guncotton used in blowing up buildings, but it must have been tremendous, as there were times when the explosions were so continuous as to resemble a bombardment."

In fact, the dynamite doomed much of the city that wasn't already burned, causing its own fires and refueling others. In Chinatown, an estimated 60 fires were started this way. Further exacerbating this misguided strategy, the Army often used gunpowder instead of dynamite, which set buildings ablaze rather than knocking them down. According to the San Francisco Chronicle, at one point the troops actually shelled buildings with artillery fire. When they did use real dynamite, flaming debris from buildings ignited natural gas from ruptured lines and caught neighboring buildings on fire.

At 8 pm on Wednesday, Jack London found himself at Union Square in the heart of the city. "It was packed with refugees. Thousands of them had gone to bed on the grass. Government tents had been set up, supper was being cooked, and the refugees were lining up for free meals." Six hours later, the square was deserted and ablaze on three sides. The refugees had moved on.

The next day the fire — and the dynamiting — continued. On Friday, with the core of the city smoldering, firefighters mounted a final, total-destruction campaign to hold the fire at Van Ness Avenue. The firebreak worked. Yet, the city was in ruins. According to the San Francisco Chronicle, "522 city blocks, 4 square miles, ... 2593 acres, [and] 28,188 buildings," were utterly destroyed.

Looting in the days after the quake was said to be rampant. According to University of Chicago history professor Mae Ngai much of it was perpetrated by the National Guard. The mayor issued an illegal "shoot to kill" order to staunch the looting, and the Army pressed citizens into work crews at gunpoint. Fearing more bad press, the city's political and business leaders reported the official death toll to be less than 500. Historians have since argued that anywhere from 3000 to 6000 people were killed. Some 300,000 had evacuated by ferry and train.

"San Francisco is gone," wrote Jack London to a nation hungry for information about the quake. "Its industrial section is wiped out. Its business section is wiped out. Its social and residential section is wiped out. The factories and warehouses, the great stores and newspaper buildings, the hotels and the palaces of the nabobs, are all gone."

The Aftermath

Within days of the quake, Governor George Pardee of California commissioned an exhaustive earthquake investigation and appointed Andrew Lawson, a University of California, Berkeley, geology professor, to lead it. In what is now commonly referred to as the Lawson Report, the investigators mapped nearly 300 miles of ruptured fault line and thoroughly documented structural damage in relation to local geology and shaking intensity.

But the hows and whys of the 1906 earthquake were still not well understood. Drawing on observations collected in the report, Henry Fielding, a geology professor at Johns Hopkins University, later proposed the theory of elastic rebound, in which pressure in the Earth's crust is built up and then released like a snapped rubber band. The theory of plate tectonics didn't gain credibility for another 50 years, but Fielding "had it all right," says Mary Lou Zoback, a geologist with the U.S. Geological Survey. The investigation is the foundation for all earthquake research that followed, Zoback adds, and it is still used today.

Another lasting product of the 1906 quake is the reconstruction that followed. Contrary to popular opinion, the disaster did not lead to better building codes. That honor goes to a 1933 earthquake that flattened several schools in Long Beach, Calif. Officials argued that onerous codes would stall the rebuilding of the city. Even today, much of San Francisco remains at risk.

"There are still thousands of hastily rebuilt, unreinforced masonry buildings cheek-by-jowl with wooden structures with no fire-resistant walls between them," reported the San Francisco Chronicle in April 2006. One study by the Association of Bay Area Governments predicts that a magnitude 7.3 quake along the San Andreas Fault near San Francisco would seriously damage 66,000 homes and force nearly a quarter of a million people into the streets.

The city improved its water-delivery system, cleared the rubble and rebuilt rapidly. Twelve insurance companies went bankrupt, but the industry paid out close to $220 million in claims. Within a few months, San Francisco's famed cable cars were carrying passengers up and down the city streets once again.